delay to control the of quantity water ?

Discussion in 'General Electronics Chat' started by abhimanyu143, Dec 26, 2015.

Aug 25, 2014
211
1
Hello
I am trying to make microcontroller based system that controls the quantity of water.
Flow Rating of water pump is 300L/H
Requirement of system : eject water near about 10 ml than stop
I don't understand according to flow rating How many second delay can be eject 10 ml water ?

2. spinnaker AAC Fanatic!

Oct 29, 2009
4,866
988
A 300 liter per hour flow rate and you can't figure how long it will take to eject 10ml? Really?

I would think that is very simple math that you should have learned in grade school. Or I missing something?

Is this RRTESH posting under a different account?

Apr 5, 2008
15,536
2,302
Hello,

300 Liter per hour = 300 / 3600 Liter per second.
This is about 83.3333 mLiter per second.
10 mLiter is 0.12 seconds of the flow.

Bertus

abhimanyu143 likes this.
4. Picbuster Member

Dec 2, 2013
356
48
No way to get this to work with a normal pump. In theory yes in the field no.
You should use a displacement pump each compartment having 10mL.
(working: take a hose place n pins on a disk and feed the hose over the pins
when disk starts to rotate is will force the water out. the distance between the pins and diameter hose will give you 10mL.)

5. Alec_t AAC Fanatic!

Sep 17, 2013
5,592
1,070
...assuming the flow rate is constant. However your pump can't start and stop instantly, so the flow rate won't be constant, so the pump will have to run longer than 0.12s. How do you plan to measure the amount of water actually dispensed?

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6. BR-549 Well-Known Member

Sep 22, 2013
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352

Aug 25, 2014
211
1
[QUOTE post: 941058, member: 217914"]...assuming the flow rate is constant. However your pump can't start and stop instantly, so the flow rate won't be constant, so the pump will have to run longer than 0.12s. How do you plan to measure the amount of water actually dispensed?[/QUOTE]
I have device that show the quantity of water in liter. I need not exact 10ml but it should be near about 10 ml

8. spinnaker AAC Fanatic!

Oct 29, 2009
4,866
988
I have device that show the quantity of water in liter. I need not exact 10ml but it should be near about 10 ml[/QUOTE]

It is going to depend on the accuracy of the pump is what Alec was trying to say. You just might pump far more than 20ml by the time the pump shuts off. No way to tell if it suits your needs without more data on the pump or simply trying it.

9. wayneh Expert

Sep 9, 2010
11,921
2,856
It would make more sense, in my opinion, to use the pump to develop a steady head pressure - perhaps within a recirculation loop - and then control the water ejection with a solenoid valve. The one-shot displacement pump is also a good option. There's no way to deliver precisely 10mL using a pump rated at 83mL/sec (thanks Bertus), with a gauge that reads in liters.

Depending on what you are doing, you might want to look at lab equipment that is designed for repeating delivery of a set volume. Automatic pipettors, petri dish fillers, that sort of thing. No need to reinvent the wheel.